Centrifugal casting mold



June 1, 194.3. s. B. RITCHIE CENTRIFUGAL CASTING MQLD Filed June 27. 1941- INVENTOR 5:0 ELRH chiE ATTORNEYS n .T Q

\\\\\\\ @Efiism Patented June 1, 1943 OFFKCE cnn'rnrrncar. casrmc MOLD Scott B. Ritchie, United States Army, Cootes Store, Va.

Application June 27, 1941, Serial No. 400,043

lGranted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 2 Claims.

The invention described herein may be manufactured and use by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a mold for centrifugal casting.

A common expedient in centrifugal casting is to employ a chill mold received in and fixed to a sleeve rotor for rotation therewith. The mold in such cases is spaced from the sleeve rotor by -circumferentia1 ribs, and various sized molds may be employed in a single size of rotor. The mold is fixed to the end of the rotor remote from the driving end thereof by means of a flange, and a clearance is provided between the ribs and the rotor to allow for radial expansion when the mold is heated by the molten metal.

It has been found that if the ribs freeze to the rotor prior to the attainment of maximum longitudinal expansion the mold is likely to be damaged by warping or cracking. This freezing is prevented, in part, by providing clearance between the ribs and rotor, but such clearance is limited by consideration of stability of the cen trifugal action.

According to the invention, longitudinal expansion is permitted after freezing of a rib to the rotor by providing a yielding connection between the mold and rotor.

It is therefore, an object of this invention to provide a centrifugal casting device in which the danger of cracking or warping due to restrained longitudinal expansion is greatly reduced.

To these and other ends, the invention consists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing wherein:

The single figure shows a longitudinal section of a chill mold and rotor.

Referring to the drawing by characters of reference, there is shown a chill mold l receivedin a rotor 2 and having a flange 3 abutting the end of said rotor and fixed thereto by stud bolts 4; carrying spring washers A reduced flange 0 serves as a bearing. The mold l is provided with flanges i which, together with flange 6, have a clearance from the walls of the rotor 2 which clearance, for example, could be of the order of 0.005 in. but which may vary for instance with the size and material of the mold and the maximum temperature of the run.

The drive is communicated to the rotor from a shaft 8 through a spider 9 which provides an exit for gases.

The heat is poured into the mold at the bolted end and both radial and longitudinal expansion commence, the point of maximum activity coinciding with the region of highest temperature, determined by the point of pour contact and the dimensions of the mold. Ordinarily this will occur between the flange 6 and the next succeeding flange I. At the first exertion of the expansive forces the mold I will progress into the rotor. 2. After the hottest of the flanges 1 contacts the rotor 2, inward extension of that portion of the mold up to such flange is inhibited. For this portion the expansion is then outward against the pressure of the spring washers 5 while the balance of the mold continues to expand inwardly until all flanges are in contact with the rotor 2.

I claim:

1. In a centrifugal casting machine including a driving rotor and a cylindrical chill mold received therein, an external annular rib integral with the mold in the vicinity of the pour point, said rib arranged to loosely space the mold from the rotor at incipient temperatures, a driving connection between the rotor and the mold, and resilient means in the driving connection for the longitudinal yielding retention of the mold to the rotor, said rib and resilient means adapted to permit longitudinal expansion of the mold in two directions after contact of a rib with the rotor.

2. In a centrifugal casting machine including a driving rotor and a cylindrical chill motor received therein, a plurality of external annular ribs integral with and spaced lengthwise of the mold, said ribs arranged to loosely space the mold from the rotor at initial temperatures, a flange on said mold covering an end face of the rotor and secured thereto by fastening means, resilient means in said fastening means for the longitudinal yielding retention of the mold to the rotor, said ribs and resilient means adapted to control progressive longitudinal expansion of the mold.

SCOTT B. RITCHIE. 

